Hydraulic turbine.



w. w. HARRIS.

HYDRAULIC TURBENB APPLICATION ElLE D Nov. 6, I916.

ffi a raw a y unirnn snares rarnnr CHARLES W. HARRIS, F SEATTLE, WASHINGTON.

HYDRAULIC TURBINE.

LZdKSSt).

Application filed November 6, 1916.

- To all whom it may concern:

Be it known that I, CnARLEs W. HARRIS, a citizen of the United States, and a resident of Seattle, in the county of King and State of l/Vashington, have invented certain new and useful Improvements in Hydraulic Turbines, of which the following is a full, true, and exact specification.

My invention relates to improvements in hydraulic turbines and more particularly to improvements in buckets for impulse wheels and has for its principal object to provide an improved and novel means of preventing excessive over-speeding of turbine wheels; to provide a bucket of such novel and peculiar construction that the action of a jet of water against its face produces a given speed of a wheel while the action of the rear of the bucket against the jet of water retards the speed of the wheel beyond a certain predetermined speed, thereby preventing racing. In turbine construction of the impulse type it is usual to design the turbine to withstand speeding to the extent of 100 per cent. normal speed and to provide governor means for controlling the speed of the wheel either by varying the load or by throttling the jet. It is obvious that wheels designed to stand 100 per cent. overspeed will necessarily be quite expensive and will be much heavier than it would be necessary if positive automatic means were provided which, independent of any governor, would prevent the wheel speeding beyond a pre-determined percentage which would not exceed 50 per cent. overspeed. My improved bucket has been scientifically designed to automatically and independently of any load or governor action, limit the overspeed to not in excess of 50 per cent. of normal speed.

Other objects will appear as my invention is more fully explained in the following specifications, illustrated in the accompanying drawing and pointed out in the appended claims.

In the drawings, Figure 1 is a perspective view of the front of my improved bucket. Fig. 2 is a similar view of the back of same. Fig. 3 is a cross sectional elevation taken along line (0-?) of Fig. 1. Fig. 4: shows the turbine wheel partially equipped with my improved buckets with a jet shown striking the buckets.

Referring more particularly to the drawings, numeral 1 indicates a shaft to which is secured a turbine wheel rotor 2. Around Specification of Letters Patent.

Patented Nov. 2'7, 19M.

Serial No. 129,640.

the periphery of the rotor 2 buckets 3 are fastened at a uniform spacing and radially with respect to the rotor. The buckets are preferably removably attached to the rotor. A jet of water 4. which issues from nozzles 5 is trained against buckets 8 in a line which is approximately tangent to the rotor. Of the buckets 3 shown in Fig. 4': the one to the left will be hereafter known as the first bucket; the middle one as the second bucket and the one to the right as the third bucket. All of the buckets 3 around the periphery of the rotor 2 are similar and the following description on one bucket will apply to them all. My bucket includes twin bowls 6 which are separated by a thin rib 7. Bowls 6 are intercepted at their outermost edge by chutes 8. The bottoms of chutes 8 are approximately tangent to the bottoms of the bowls 6 and their sides are a continuation of ribs 7 and of the inner face of bowls 6. The chutes preferably widen and deepen as they approach the intersection with the bowls. The bottom lines of the chutes 8 are approximately radial with respect to the rotor as will be more clearly shown in Fig. 4. The bowls 6 are preferably of hemispherical shape. It will be noted that the chutes form an appendage to the outer end of the bucket proper and are so shaped and designed as to guide the jet 4c into the bowls of the bucket along lines which are tangent to the bottom and side of the bowl and with as little breaking up of the jet as possible. It will be noted that the first bucket shown in Fig. 4. has only partially intercepted the jet and the movement of the water with respect to the chutes and bowl is illustrated in this figure. The function of the extended chute portions of the bucket is to increase the angle between the direction of the motion of the bucket as it enters the jet and the line of action of the jet. This angle is indicated by X in Fig. i. The back of the appendage or spout portion of the bucket is curved and hollowed as at 9 to form a suitable surface for the intercepted portion of the st to exert a backward pressure against at such time as the bucket will be traveling beyond a pro-determined speed with respect tothe jet. This curved portion 9 will be called the rear face of the bucket. The exact shape of the rear face of the bucket varies somewhat depending on different conditions and is a function of the diameter of the wheel and the position of the line of action of the jet with respect to the center of the wheel. It will be seen in Fig. i on the first bucket that the outline of the rear face follows closely the surface of the intercepted portion of the jet between the first and second buckets and that as the first bucket moves down through the jet that the rear face will wipe along the rear of the intercepted portion of the jet. It is understood of course, that the intercepted portion of the jet between the first and second buckets is constantly shortening as the wheel revolves, due to its constant pressure against the second bucket. The wheel as shown in Fig. 4- will be assumed to be revolving at normal speed and supposing that the load on the wheel should be removed, thereby allowing the wheel to freely race. As the buckets speed up they will reach a point where the rear faces 9 of the buckets will strike against the intercepted portions of the jet between the buckets. It will therefore be apparent that the inter cepted portions of the jets are exerting a retarding pressure against the rear face of the buckets. It will also be understood that as the speed of the wheel increases the normal action of the et striking the bowls of the buckets becomes less elfective as the velocity of the bucket and jet approach. each other, and also the rear face of appendage on speeding bucket-s strikes the intercepted portions of the jet at an angle and tends to deflect it away from the buckets in front, these buckets being cut away to admit the joining of the chute. A slight deflection of the intercepted portion of the jet assists materially in the regulation by permitting this portion of the jet to pass the buckets without striking them or to strike them with a deflecting blow which is inefficient. The back pressure of the intercepted portion of the jet will increase as the velocity of the buckets increases. It will be apparent from the foregoing that a point will be reached Where the retarding action of the intercepted portions of the jet against the rear faces of the buckets will be sufficient to counteract the force of the jet sufliciently to hold the wheel at a speed above which the given jet can not be made to force the wheel. A number of wheels have already been equipped with my improved buckets and some of them have undergone extensive practical tests under ordinary operation conditions, while others have undergone laboratory efficiency tests. All of the above tests have proved conclusively that my improved buckets prevent overspeeding in excess of 50 per cent. of the normal rate of speed even though all of the load be removed from the wheel.

While I have shown a particular form of embodiment of my invention, I am aware that many minor changes therein will readily suggest themselves to others skilled in the art without departing from the spirit and scope of the invention, and I therefore desire to avoid being limited to the eXact form shown and described.

Having described my invention, what I claim as new and desire to protect by Letters Patent, is- 1 1. In a turbine wheel, the combination of a series of impulse buckets which are adapted to intercept a fluid jet, means integral with the rear faces of said buckets to antomatically prevent overspeeding of the wheel, said means being constructed and arranged to engage and deflect the intercepted portions of the said jet from engagement with the bowl of the next forward bucket, whereby the force of said intercepted jet is diminished and the speed of the wheel is regulated.

2.'A hydraulic turbine bucket provided with means on the back of the bucket for automatically preventing speeding, said means being constructed and arranged to engage and deflect the intercepted portion of a moving jet. 7

In a turbine wheel, the combination of a series of impulse buckets which are adapted to intercept a fluid jet, means integral with the rear faces of said buckets for preventing overspeeding of the wheel by engaging the intercepted portions of the jet whenever the ratio between the lineal velocity of the buckets and the jet becomes greater than a pre-determined ratio; said means including a curved rear face on each of said buckets, the said curve commencing in a line which is approximately radial with respect "to the wheel and terminating in a line which is approximately tangent to the wheel.

4. In a turbine wheel, the combination of a series of impulse bucketswhich are adapted to intercept a fluid jet, means integral with the rear faces of said buckets for automatically preventing overspeeding of the wheel by engaging the intercepted portions of the jet whenever the ratio between the lineal velocity of the bucketsand the jet becomes greater than a pre-determined ratio.

5. In a device of the class described, the combination of impulse bucket means mounted upon the periphery of a rotor and adapted to intercept a fluid jet; said bucket means including a hemispherical bowl in the front face of said bucket, an appendage extending outwardly beyond said bowl, a chute cut in the face of said appendage and intercepting said bowl, whereby when the bucket intercepts the jet the fluid will be guided into the bowl.

6. In a device of the class described, the combination of impulse bucket means mounted upon the periphery of a rotor and adapted to intercept a fluid jet, said bucket means including a hemispherical bowl in the front face of said bucket, an appendage extending outwardly beyond said bowl, a chute cut in the face of said appendage and intercepting said bowl, whereby when the bucket intercepts the jet the fluid will be guided into the bowl, and a curved rear face oppositely disposed to said chute, said curve being of such shape as to wipe along the rear end of the intercepted portion of said jet when the turbine is traveling at normal speed and to bear against the intercepted portion of said jet when traveling at excessive speed, whereby the resistance of said intercepted portion will check the speed of the said turbine.

7 In a hydraulic impulse turbine, the combination of automatic and positive speed limit means, said means including appendages on the outer ends of the turbine buckets which are provided with approximately radial chutes in their front faces, whereby the angle between the direction of the motion of the bucket which is entering the jet and the line of motion of the jet is increased, a forwardly curved rear face on said bucket, the said curve being of such shape as to wipe along the rear end of that portion of the jet which is adjacent the rear of the bucket when the wheel is rotating at normal speed, and to strike against the said portion of the jet when the speed of the wheel is in excess of normal speed.

8. In an impulse turbine wheel which is driven by the action of a jet against a series of buckets arranged around the periphery of said wheel, the combination of bucket means which automatically prevents excessive speeding of the wheel; said means including twin hemispherical bowls in the front face of said bucket, an appendage eX- tending beyond the outer most edge of said bowls, chutes intercepting the said bowls and extending therefrom in an approximately radial direction with respect to the said wheel, whereby when the bucket first enters the jet the jet is guided into the bowls and the angle between the direction of motion of the bucket and the entering jet is a maximum, a curved rear face on the back of the bucket, the line of said curved face being such that as the wheel revolves at speeds in excess of normal speed the said face will strike against the rear end of the intercepted portion of the jet which lies between the said bucket and an adjacent bucket, whereby the speeding of the wheel will be reduced by the resistance of the intercepted portion of the jet against the rear face of the bucket.

CHARLES W. HARRIS.

copies of this patent may be obtained for five cents each, by addressing the Gommiasioner of IPatenta Washington, D. G. 

